Integrating urban drainage within a rainfall based Flood Risk Assessment model and the impact on Flood Hazard

摘要

Seeking to develop urban Flood Risk Assessment (FRA) modelling, this paper reviews the degree to which an existing TUFLOW (BMT WBM, 2009) 100yr event rainfall FRA model of a densely populated UK town is enhanced by dynamically linking the 2D overland model to a new 1D urban drainage and sewer network model. The hydrodynamic 1D-2D model details road drainage features such as kerb-side gutter channels and gully inlets connecting the urban surface model to a subsurface storm sewer network. This is used to assess the impact of integrating urban drainage on the overall FRA flood result in terms of inundation (peak depths and extents). The paper further considers potential application through the use of maximum velocity to map Flood Hazard to both people and infrastructure (DEFRA, 2005). Results indicate that while integrating urban drainage has significant impact on inundation result, the wider Flood Hazard prediction remains largely unaffected.